The present invention relates to a tool and a cutting insert for milling, especially disc milling.
In disc milling cutters, the periphery of the rotary milling body is equipped with a number of circumferentially spaced-apart cutting inserts, which protrude alternately from opposite sides of the milling body. The relative displacement of the cutting inserts is made in order to obtain, in the workpiece, clearance and in order to obtain grooves having perpendicular bordering surfaces. The bottom surface of the groove is provided by means of the major cutting edges of the cutting inserts, while the side surfaces of the groove are provided by means of the minor cutting edges extending substantially perpendicularly to the major cutting edges. Radii between the bottom surface and the side surfaces of the groove are obtained by means of somewhat rounded cutting corners at a transition between associated pairs of major and minor cutting edges of the cutting insert. The relative displacement to opposite sides of the milling body requires that the cutting inserts be provided in right-hand and left-hand embodiments in order to guarantee the requisite clearance between the side wall and the portion of the cutting insert following the minor cutting edge.
Through EP-A-0 873 808 a single sided cutting insert is previously known, which comprises only two, but different, cutting edges, to avoid possible mix-up by the operator. The known cutting insert means poor utilization of the possibilities of the cutting material. In Qvarth U.S. Pat. No. 5,454,671, another single sided cutting insert is shown.